1. Field of the Invention
The present invention relates in general to the field of information handling system bus communication, and more particularly to a system and method for dynamic adjustment of an information handling system graphics bus.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems present visual information as images by communicating the visual information to a display having evenly distributed pixels. Typically, a graphics controller converts digital visual information generated by processing components of the information handling system the LVDS format to indicate the color of each pixel in the display. Images on a display are maintained by periodically refreshing the pixels with new or the same color, typically in a scan pattern. Image quality varies in resolution, generally measured by the number of pixels in a display, and the clarity with which movement is depicted. Displays that have greater numbers of pixels will present the visual information with better resolution, however, increased resolution means increased amounts of visual information for communication to the pixels. Similarly, graphics controllers that have more powerful processing capability will present moving images with greater clarity, however, the presentation of moving images with high clarity tends to require communication of relatively large amounts of information. As an example, communication of a typical operating system desktop image uses a relatively small bandwidth of approximately 250 KB/s. In contrast, communication of high bit rate video streaming with a video decode acceleration graphics subsystem uses a bandwidth of approximately 1 GB/s and a three dimensional application with a high resolution display and anti-aliasing uses bandwidth of approximately 2 GB/s.
In order to handle the increased amounts of visual information communicated in support of high resolution displays, industry has turned to PCI Express compatible buses. PCI Express has a 16 lane width for rapidly communicating high volumes of information. However, power consumption and thermal output is substantial during operation of the full 16 lanes of width. In particular, portable information handling systems that run on internal battery power of limited duration and that have small housings with tight thermal constraints have difficulty incorporating a PCI Express bus. To reduce the impact of PCI Express power consumption and thermal output on portable information handling systems, a PCI Express bus is sometimes transitioned from 16 lane width to one lane width when the portable information handling system transitions from external to internal power or when manually overridden by a user interface. One problem that arises with the transition of the PCI express bus to a single lane width while operating on internal battery power is that system performance can degrade, such as by dropping frames of information that exceed the bus single lane width's ability to carry information, resulting in a poor user experience. If a user attempts to correct the degraded performance by increasing the bus width, the user will experience decreased battery run time.